Joining metals



I State of Ohio,

July 15, 1924.

Patent THOMAS MIDGLEY, JR., OF DAYTON, OHIO,-

ABSIGNO'B, BY HESN'E ASSIGNMENTS, TO

GENERAL MOTORSRESDARCE CORPORATION, OF DAYTON, OHIO, A RPOmION..

OF DELAWARE.

JOINING METALS.

Application mea January as, 192e. serial No, 554,170.

To all whom t may concern:

.Be it known that I, THOMAS MIDGLEY, Jr., a citizen of the United States ofAmerica, residing at Dayton, county of Montgomery, have invented certain new and useful Improvements inv J oinin Met-als, of which the following is a full, c ear, and exact description.

This invention relatesto the joining together of metals, and one object ofthe invention is to provide for joining together metals, which ma not be readily and satisfactorily joined by the usual methods, in such wise that a substantially uniform bond is secured between them. Another object of the invention is to prof videl a method of attaching cooling elements, such as copper fins, to an engine cylinder, so that eifectivethermal conductivity across the bond of the cylinder and cooling elements is secured.

Other objects and advantages of the present inventionwill be apparent from the description set out below, when taken inA connection with the accompanying drawing, in

- which,

Fig.1 is a View showing the' firststep in the preparation of a paratus for. effecting the joining of copper ns to a cylinderwhic consists in forminga core, containing the Fig. 2 shows a completed core j F'` 3 is a sectional view of an engine .cyliller, coated with` soldering material, ready for the joining operation;

4 is a sectional view of the apparatus in w ich the joining of the two metals is accomplished, showing the coated cylinder and core, containin the cooling elements, in roperly assemb ed relation o plis ing the joining thereof; and

Fig. 5 is a sectional view of a completed cylindery after the 'joining operation has taken lace.

Whl e this invention is generally .applicable to the joining of a pluralit of metals to secure a ood bond between t em, it has been worke out primaril with the attachment of coo in elements, or fins, to anengine cylinder an lfor urposes of easier description, the joining o copper finsV to a steel or cast iron en `ne cylinder'is set out It is to be understood,1 however, that 'fundamenta snugly against the former. in connection the invention is by no means limitedto this specific adaptation'. In the joining of copper fins to a cylinder the lins are arra ed in their proper positions, being embed ed within a core or otherwise protected exce t as to those parts which are to be actua y joined to the cylinder, the fcylinderis laced Within the fins, in properly spaced re ation thereto, and soldering material is then run .around the unprotected ends of the fins, and -a joining of the lins to the cylinder thus secured.

.An engine cylinder of the type shown in Fig. 5 comprises a cylinder portion 10 to which is attached a plurality of lins 11. In `the cylinder disclosed these lins are ofcopper, or some other metalof good thermal conductivity, and are made u from, comparatively, thin sheet co per. or purposes of easier `manufacture 't e fins are prefer, ably made from a continuous sheet of co` per which is bent upon itself, or corru ate as shown; but, if desired, they may made separately, instead of in one piece. The

method of `'oining them to the cylinder is yv the same, in, each case however; f

In carrying this method into eect the fins arepositioned about afformer 15 which is preferably made of a metal such as aluminum. However, it may, of course, be made of any other vdesired metal. This former is provided in the periphery thereof with slots or rooves, 16, adapted to receive the inner endgs of the fins when they are assembled about the former. As shown in the drawing, the former is adapted for`vertically arranged nsand consequentlythe slots 16 are arranged longitudinally thereof. The fins having been assembled, and properly arranged in the slots 16, a metal tube 17 is arranged about them. This tube is made of the proper diameter to just snugly enclose thelins when t e are assembled upon the former. If desire the tube 17 may haveclamping elements associated therewith adapted to hold the fins The s ace between the former and the tube, an around the fins is next filledp with some refractory material, such as core sand. An other desired material may be used, but 1t has been found that core sand functions very liti!- factorily. This `sand is tamped down firmly ss n.

los

into place, so as to form eect a core, within the tube 17, in which the eater art l of the fins is embedded. As is o vious rom the drawin so much of the fins as is positioned within the grooves or slots 16 is not covered by the sand. The completed core is shown in Fi 2, in which the parts of the ns arrange within the slots are shown extending into the space within the core.

Prior to the ctual joining operation, and

in order to insu e more satisfactory bonding of the ns to the cylinder, the cylinder, 10, is

coated with a layer of material 20, which will tioned that the core containing the fins will be adapted to freely receive the coated cylinder within the s ace defined by the inner ends of the fins, t e cylinder and core when assembled bei so arranged that a space is left between t e cylinder kand the core for receiving soldering material. In order to n securely close up the lower end of this space and pevent the solder from running therefrom fore it has had an opportunity to cool and set, the pan is illed with a material 26, adapted to securely dam up the lower end of the space. A number of materials could no doubt be used but it has `quite simple. The core been found that a paste consisting of whitmixed with water lass functions very satisfactorily indeed. i mixture of borax and sand has been found to function satisfactorily in this relation, but the whitin and water glass mixture is thought pre erable. The pan is adapted to rest upon a metaltable 27 having supports 28 dependmg therefrom and adapted to hold the burner 29 to which fuel is supplied through the pi e30 controlled by means of the valve 31. y means of this burner the pan, with vits contained material, the cylinder and the core' are brought to a temperature above 'the melting ypoint of the solder used, so that the solder which is solidified during the pouring operation may be completely melted and a good bond thus secured. To assist 1n maintaining the proper heat conditions durm the joining operation, the table 27 is provi ed with supports 32 upon which is placed a cylindrical metal sleeve 33, adapted to cause substantially all the heatfrom the burner` 29 to aect the pan, cylinder, core and soldering' material. l

The method of'i'ning finsto a cylinder is j having been properly prepared, and the cylinder, preferably,

coated the two are placed upon the pan 2.5, with the lower end thereof sealed by the mixture 26 and 4the burner 29 is started. Molten solder is then poured into the space between the cylinder and the core. Some of the solder will solidify but the heat from the burner soon brings the entire apparatus up to a temperature which will insure melting of all the solder. run down into the space between the c 1inder and core, and a good boudin o the ins and the cylinder will result. e apparatus is then allowed to cool down, the solder to set, and the sand then cleaned from the fins.

It is not necessary that the cylinder and The solder will then core be placed upon the pan 25 and the soldering material poured therebetween. If desired the cylinder and core may be clamped yin properly spaced relation and immersed in a bath of soldering material. Where this method of bonding is used, however, care must be taken to prevent the solder running out from between the cylinder and core when the apparatus is removed from the bath of solde-r.

While the method herein described, constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise method, and that changes may be made without departing from the scope of the invention which is defined in the appended claims.

What I claim is as follows:

l. The` method of joining fins to an engine cylinder which consists in forming a core containing said fins, and having the inner ends of the fins unprotected; placing the cylinder within the core and in pro erly spaced relation to the unprotected en s of the fins; dammin the lower end of the space between the cy inder and core to prevent the. How of molten soldering material therethrough; and pouring molten soldering material wlthin said space.

2. The method of joining fins to a cylinder which consists in forming a core containing said fins, arranged in properl spaced relation, and having the inner en thereof unprotected; coating the ,cylinder to which the fins are to be `oined, with soldering material; placingt e cylinder within the core and in properly spaced relation thereto; damming the lower end of the space between the cylinder and core to prevent the flow of soldering material therefrom; and pouring soldering material into the s ace between the cylinder and core, and a ut the unprotected ends of the-fins.

3. The method of joining copper cooling fins to an engine cylinder composed of a wear resisting metal which consists in assembling the fins within a core with the inner ends thereof unprotected; coating the cylinder with a material adapted to facilitate the bonding of the soldering material to said the cylinder, and the fins toa temperature cylinder; placing the coated cylinder within adapted-to cause a free low of the solder- 10 the core and in properly spaced relation to in? maerial within said space. the unprotected inner ends of the fins; runn testimony whereof I aix m si ature. e soldering material into said space THOMAS MIDG E JR.

w e at the same time preven the escape Witnesses: of the molten soldering materi from said Mmmm) Pmnn, space; Yand heating the soldering material, ALVINA LnmnN. 

